small bug fixes

fixed bug in NeuronLayer::setDesiredOutputValue (wrong layerErrorValue calculation)
fixed bug in neuronlayertest (compare values with cmath::equals)
added ifdefs to enable compilation without eigen3
reviewed benchmarks

changed network configuration of networks in iris and housing bench
changed housing dataset (scaled output data between 0 and 1)
quickprop network added to benchmarks
Merge branch 'master' into arch

Conflicts:
	benchs/housingbench.cpp